textproduct: Quad Cities

KEY MESSAGES

- Beautiful summer weather through Friday.

- Patchy fog overnight, especially in low lying areas and river valleys.

- Warmer this weekend, with a return to an active weather pattern next week and increasing humidity.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 154 PM CDT Thu Aug 27 2026

Pleasant late summer weather continues, with a large area of high pressure over the northern Plains and the upper Midwest. As of 1 pm, temperatures were in the lower 80s, with some scattered fair wx Cu overhead around 4-5kft. Earlier this morning, there was haze/smoke aloft seen over southern MN and northern IA and has since become less pronounced.

Another deep mixing day similar to yesterday, will result in widespread highs topping out in the low to mid 80s. Tonight, surface high to move overhead bringing clearing skies and pleasant conditions overnight for ideal viewing of the partial lunar eclipse. Patchy fog will also be possible prior to sunrise, especially in river valleys and low lying areas. Some models show widespread dense fog and disagree on area placement tonight. Can't rule out some areas of fog occurring, but not confident on spatial extent and how low we will get to add into the forecast yet. Any fog that occurs will quickly lift/burn off after sunrise. Lows to drop into the upper 50s/low 60s, which is near normal for late August.

Friday, a rinse and repeat forecast is expected with plentiful sunshine and highs in the low to mid 80s. Return flow develops on the backside of the surface high Friday night, resulting in slightly warmer temperatures in the lower 60s.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 154 PM CDT Thu Aug 27 2026

Upper ridge over the central CONUS to break down Saturday, as a strong upper low arrives onshore in the Pacific Northwest. A few lead shortwaves will round the top of the flattening ridge providing us with increasing temperatures, humidity levels, and precipitation chances late weekend and into next week. The first shortwave to arrive Saturday, with recent model trends showing a decaying line of showers/storms during the late morning hours across northern and northeast IA. Forecast soundings and time height cross sections show plenty of dry air for this activity to overcome leading to light QPF amounts under 0.10" mainly confined to areas northwest of Cedar Rapids. After this wave, recent model trends show the main storm track remaining to our northwest over the upper Midwest which would keep us warm and dry for the rest of August. For now, will stick with NBM slight chance/chance PoPs Sunday and Monday, but am inclined these will be removed in later forecasts.

Sunday onward, there is higher confidence of building heat and humidity with 594 dam upper high centered over southern Missouri. 850 mb temps are progged to rise into the 21-25C range and combined with dewpints in the upper 60s/low 70s will result in highs in the upper 80s/low 90s and heat indices approaching 100 degrees at times through Thursday. NBM probabilities of 70+ degree dewpoints are in the 50-80% range Sunday through Thursday. In addition, the latest CPC 6-10 day temperature outlook has 90% or higher combined probabilities of near/above normal temperatures for the Sept 1st-5th timeframe. It looks like late summer heat will arrive prior to the Labor Day weekend. However, as noted by the previous shift there remains a large temperature spread in high temps (6-9 degrees) next week due to the strength and placement of upper ridge and any precip chances. For this reason, capped highs to remain under 93 degrees and left the daily PoPs from the NBM alone. Depending on when the upper ridge slides east or retrogrades westward will be key when we see precip chances and any relief from the heat as well as any severe risk. With large model variability, it is hard to pin this down at this time range.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 545 PM CDT Thu Aug 27 2026 Upper level smoke will be present at times, but not expecting any impacts to the terminals. Otherwise, high pressure looks to dominate through the period providing light winds and predominantly VFR conditions. That said, the ideal radiational cooling setup will support at least patchy fog, especially in river valleys and other low-lying areas. Plan to keep the mention of a short period of MVFR visibility at all sites 10z-13z, and continue with an IFR visibility mention at BRL where dew point depressions are progged to be lower.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.